I've had an AP for Disneyland since 2006 when I moved back to northern California. For me Disneyland and WDW are two similar, yet very different experiences. I think Disneyland itself is far superior to the MK, but Epcot is my 2nd favorite park.

WDW's immersion factor is huge for me. I don't think I'll ever pay to stay offsite at WDW because that would make it a very expensive trip just to visit Epcot. It's not that I dislike the other parks, but the MK and DHS offer a lot of what Disneyland already has and Animal Kingdom isn't a compelling enough reason for me to visit. Yes, I spend a day there when I visit, but it's not my reason to go. Having that total immersion is really magical for me and helps make WDW special for me.